Method and system for displaying changes of source code

ABSTRACT

Methods and systems consistent with the present invention provide an improved software development tool which displays versions of source code with the indications of the edits in a graphical representation, wherein the graphical representation of the source code is not merely a text representation on a user interface. Each version reflects an instance in an edit history, i.e., reflects the changes made to the source code.

CROSS-REFERENCE TO RELATED APPLICATIONS

The following identified U.S. patent applications are relied upon andare incorporated by reference in this application:

-   -   U.S. Provisional Application No. 60/157,826, entitled “Visual        Unified Modeling Language Development Tool,” filed on Oct. 5,        1999;    -   U.S. Provisional Application No. 60/199,046, entitled “Software        Development Tool,” filed on Apr. 21, 2000;    -   U.S. patent application Ser. No. 09/680,063 entitled “Method And        System For Developing Software,” and filed on the same date        herewith;    -   U.S. patent application Ser. No. 09/680,030 entitled “Method And        System For Generating, Applying, And Defining A Pattern,” and        filed on the same date herewith; and    -   U.S. patent application Ser. No. 09/680,064 entitled “Method And        System For Collapsing A Graphical Representation Of Related        Elements,” and filed on the same date herewith.

FIELD OF THE INVENTION

The present invention relates to a method and system for developingsoftware. More particularly, the invention relates to a method andsystem for tracking changes made to source code, and displaying thesource code with these changes.

BACKGROUND OF THE INVENTION

Computer instructions are written in source code. Although a skilledprogrammer can understand source code to determine what the code isdesigned to accomplish, with highly complex software systems, agraphical representation or model of the source code is helpful toorganize and visualize the structure and components of the system. Usingmodels, the complex systems are easily identified, and the structuraland behavioral patterns can be visualized and documented.

The well-known Unified Modeling Language (UML) is a general-purposenotational language for visualizing, specifying, constructing, anddocumenting complex software systems. UML is used to model systemsranging from business information systems to Web-based distributedsystems, to real-time embedded systems. UML formalizes the notion thatreal-world objects are best modeled as self-contained entities thatcontain both data and functionality. UML is more clearly described inthe following references, which are incorporated herein by reference:(1) Martin Fowler, UML Distilled Second Edition: Applying the StandardObject Modeling Language, Addison-Wesley (1999); (2) Booch, Rumbaugh,and Jacobson, The Unified Modeling Language User Guide, Addison-Wesley(1998); (3) Peter Coad, Jeff DeLuca, and Eric Lefebvre, Java Modeling inColor with UML: Enterprise Components and Process, Prentice Hall (1999);and (4) Peter Coad, Mark Mayfield, and Jonathan Kern, Java Design:Building Better Apps & Applets (2nd Ed.), Prentice Hall (1998).

As shown in FIG. 1, conventional software development tools 100 allow aprogrammer to view UML 102 while viewing source code 104. The sourcecode 104 is stored in a file, and a reverse engineering module 106converts the source code 104 into a representation of the softwareproject in a database or repository 108. The software project comprisessource code 104 in at least one file which, when compiled, forms asequence of instructions to be run by the data processing system. Therepository 108 generates the UML 102. If any changes are made to the UML102, they are automatically reflected in the repository 108, and a codegenerator 110 converts the representation in the repository 108 intosource code 104. Such software development tools 100, however, do notsynchronize the displays of the UML 102 and the source code 104. Rather,the repository 108 stores the representation of the software projectwhile the file stores the source code 104. A modification in the UML 102does not appear in the source code 104 unless the code generator 110re-generates the source code 104 from the data in the repository 108.When this occurs, the entire source code 104 is rewritten. Similarly,any modifications made to the source code 104 do not appear in the UML102 unless the reverse engineering module 106 updates the repository108. As a result, redundant information is stored in the repository 108and the source code 104. In addition, rather than making incrementalchanges to the source code 104, conventional software development tools100 rewrite the overall source code 104 when modifications are made tothe UML 102, resulting in wasted processing time. This type of manual,large-grained synchronization requires either human intervention, or a“batch” style process to try to keep the two views (the UML 102 and thesource code 104) in sync. Unfortunately, this approach, adopted by manytools, leads to many undesirable side-effects; such as desired changesto the source code being overwritten by the tool. A further disadvantagewith conventional software development tools 100 is that they aredesigned to only work in a single programming language. Thus, a tool 100that is designed for Java™ programs cannot be utilized to develop aprogram in C++. Moreover, it is not possible to track the changes madeto the source code using conventional software development tools.Accordingly, unless the developer maintains detailed notes regarding thedevelopment of the source code, it is difficult to determine whatmodifications to the source code were attempted during its development.There is a need in the art for a tool that avoids the limitations ofthese conventional software development tools.

SUMMARY OF THE INVENTION

Methods and systems consistent with the present invention provide animproved software development tool which overcomes the limitations ofconventional software development tools. The improved softwaredevelopment tool of the present invention allows a developer to trackchanges made to source code, and display the source code with thesechanges. Accordingly, the developer can recollect the modifications thatwere made to the source code during the development of the source code.

In accordance with methods consistent with the present invention, amethod is provided in a data processing system for displaying versionsof source code. Each version reflects an instance in an edit history.The method comprises the steps of storing indications of the edits tothe source code, and displaying the versions of the source code with theindications of the edits.

In accordance with articles of manufacture consistent with the presentinvention, a computer-readable medium is provided. The computer-readablemedium contains instructions for controlling a data processing system toperform a method. The data processing system has versions of sourcecode. Each version reflects an instance in an edit history. The methodcomprises the steps of storing indications of the edits to the sourcecode, and displaying the versions of the source code with theindications of the edits.

Other systems, methods, features and advantages of the invention will beor will become apparent to one with skill in the art upon examination ofthe following figures and detailed description. It is intended that allsuch additional systems, methods, features and advantages be includedwithin this description, be within the scope of the invention, and beprotected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate an implementation of theinvention and, together with the description, serve to explain theadvantages and principles of the invention. In the drawings,

FIG. 1 depicts a conventional software development tool;

FIG. 2 depicts an overview of a software development tool in accordancewith the present invention;

FIG. 3 depicts a data structure of the language-neutral representationcreated by the software development tool of FIG. 2;

FIG. 4 depicts representative source code;

FIG. 5 depicts the data structure of the language-neutral representationof the source code of FIG. 4;

FIG. 6 depicts a data processing system suitable for practicing thepresent invention;

FIG. 7 depicts an architectural overview of the software developmenttool of FIG. 2;

FIG. 8A depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays a list ofpredefined criteria which the software development tool checks in thesource code;

FIG. 8B depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays thedefinition of the criteria which the software development tool checks inthe source code, and an example of source code which does not conform tothe criteria;

FIG. 8C depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays an example ofsource code which conforms to the criteria which the softwaredevelopment tool checks in the source code;

FIG. 9 depicts a flow diagram of the steps performed by the softwaredevelopment tool depicted in FIG. 2;

FIGS. 10A and 10B depict a flow diagram illustrating the update modelstep of FIG. 9;

FIG. 11 depicts a flow diagram of the steps performed by the softwaredevelopment tool in FIG. 2 when creating a class;

FIG. 12 depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays a use casediagram of source code;

FIG. 13 depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays both a classdiagram and a textual view of source code;

FIG. 14 depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays a sequencediagram of source code;

FIG. 15 depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays acollaboration diagram of source code;

FIG. 16 depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays a statechartdiagram of source code;

FIG. 17 depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays an activitydiagram of source code;

FIG. 18 depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays a componentdiagram of source code;

FIG. 19 depicts a user interface displayed by the software developmenttool depicted in FIG. 2, where the user interface displays a deploymentdiagram of source code;

FIG. 20 depicts a flow diagram of the steps performed by the softwaredevelopment tool depicted in FIG. 2 to store the edit history of sourcecode, in accordance with the present invention; and

FIGS. 21A–C depict a flow diagram of the steps performed by the softwaredevelopment tool depicted in FIG. 2 to sequentially displaying thesource code with the indications of the edit history, in accordance withthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

Methods and systems consistent with the present invention provide animproved software development tool which displays versions of sourcecode. Each version reflects an instance in an edit history, i.e.,reflects the changes made to the source code.

As depicted in FIG. 2, source code 202 is being displayed in both agraphical form 204 and a textual form 206. In accordance with methodsand systems consistent with the present invention, the improved softwaredevelopment tool generates a transient meta model (TMM) 200 which storesa language-neutral representation of the source code 202. The graphical204 and textual 206 representations of the source code 202 are generatedfrom the language-neutral representation in the TMM 200. Althoughmodifications made on the displays 204 and 206 may appear to modify thedisplays 204 and 206, in actuality all modifications are made directlyto the source code 202 via an incremental code editor (ICE) 208, and theTMM 200 is used to generate the modifications in both the graphical 204and the textual 206 views from the modifications to the source code 202.

The improved software development tool provides simultaneous round-tripengineering, i.e., the graphical representation 204 is synchronized withthe textual representation 206. Thus, if a change is made to the sourcecode 202 via the graphical representation 204, the textualrepresentation 206 is updated automatically. Similarly, if a change ismade to the source code 202 via the textual representation 206, thegraphical representation 204 is updated to remain synchronized. There isno repository, no batch code generation, and no risk of losing code.

The data structure 300 of the language-neutral representation isdepicted in FIG. 3. The data structure 300 comprises a Source CodeInterface (SCI) model 302, an SCI package 304, an SCI class 306, and anSCI member 308. The SCI model 302 is the source code organized intopackages. The SCI model 302 corresponds to a directory for a softwareproject being developed by the user, and the SCI package 304 correspondsto a subdirectory. The software project comprises the source code in atleast one file that is compiled to form a sequence of instructions to berun by a data processing system. The data processing system is discussedin detail below. As is well known in object-oriented programming, theclass 306 is a category of objects which describes a group of objectswith similar properties (attributes), common behavior (operations ormethods), common relationships to other objects, and common semantics.The members 308 comprise attributes and/or operations.

For example, the data structure 500 for the source code 400 depicted inFIG. 4 is depicted in FIG. 5. UserInterface 402 is defined as a package404. Accordingly, UserInterface 402 is contained in SCI package 502.Similarly, Bank 406, which is defined as a class 408, is contained inSCI class 504, and Name 410 and Assets 412, which are defined asattributes (strings 414), are contained in SCI members 506. Since theseelements are in the same project, all are linked. The data structure 500also identifies the language in which the source code is written 508,e.g., the Java™ language.

FIG. 6 depicts a data processing system 600 suitable for practicingmethods and systems consistent with the present invention. Dataprocessing system 600 comprises a memory 602, a secondary storage device604, an I/O device 606, and a processor 608. Memory 602 includes theimproved software development tool 610. The software development tool610 is used to develop a software project 612, and create the TMM 200 inthe memory 602. The project 612 is stored in the secondary storagedevice 604 of the data processing system 600. One skilled in the artwill recognize that data processing system 600 may contain additional ordifferent components.

Although aspects of the present invention are described as being storedin memory, one skilled in the art will appreciate that these aspects canalso be stored on or read from other types of computer-readable media,such as secondary storage devices, like hard disks, floppy disks orCD-ROM; or other forms of RAM or ROM either currently known or laterdeveloped.

FIG. 7 illustrates an architectural overview of the improved softwaredevelopment tool 610. The tool 610 comprises a core 700, an openapplication program interface (API) 702, and modules 704. The core 700includes a parser 706 and an ICE 208. The parser 706 converts the sourcecode into the language-neutral representation in the TMM, and the ICE208 converts the text from the displays into source code. There arethree main packages composing the API 702: Integrated DevelopmentEnvironment (IDE) 708; Read-Write Interface (RWI) 710; and Source CodeInterface (SCI) 712. Each package includes corresponding subpackages. Asis well known in the art, a package is a collection of attributes,notifications, operations, or behaviors that are treated as a singlemodule or program unit.

IDE 708 is the API 702 needed to generate custom outputs based oninformation contained in a model. It is a read-only interface, i.e., theuser can extract information from the model, but not change the model.IDE 708 provides the functionality related to the model's representationin IDE 708 and interaction with the user. Each package composing the IDEgroup has a description highlighting the areas of applicability of thisconcrete package.

RWI 710 enables the user to go deeper into the architecture. Using RWI710, information can be extracted from and written to the models. RWInot only represents packages, classes and members, but it may alsorepresent different diagrams (class diagrams, use case diagrams,sequence diagrams and others), links, notes, use cases, actors, states,etc.

SCI 712 is at the source code level, and allows the user to work withthe source code almost independently of the language being used.

There are a variety of modules 704 in the software development tool 610of the present invention. Some of the modules 704 access information togenerate graphical and code documentation in custom formats, export todifferent file formats, or develop patterns. The software developmenttool also includes a quality assurance (QA) module which monitors themodifications to the source code and calculates the complexity metrics,i.e., the measurement of the program's performance or efficiency, tosupport quality assurance. The types of metrics calculated by thesoftware development tool include basic metrics, cohesion metrics,complexity metrics, coupling metrics, Halstead metrics, inheritancemetrics, maximum metrics, polymorphism metrics, and ratio metrics.Examples of these metrics with their respective definitions areidentified in Tables 1–9 below.

TABLE 1 Basics Metrics Basic Metrics Description Lines Of Code Countsthe number of code lines. Number Of Attributes Counts the number ofattributes. If a class has a high number of attributes, it may beappropriate to divide it into subclasses. Number Of Classes Counts thenumber of classes. Number Of Import Counts the number of importedpackages/ Statements classes. This measure can highlight excessiveimporting, and also can be used as a measure of coupling. Number OfMembers Counts the number of members, i.e., attributes and operations.If a class has a high number of members, it may be appropriate to divideit into subclasses. Number Of Operations Counts the number ofoperations. If a class has a high number of operations, it may beappropriate to divide it into subclasses.

TABLE 2 Cohesion Metrics Cohesion Metrics Description Lack Of CohesionOf Takes each pair of methods in the class and Methods 1 determines theset of fields they each access. A low value indicates high couplingbetween methods, which indicates potentially low reusability andincreased testing because many methods can affect the same attributes.Lack Of Cohesion Of Counts the percentage of methods that do not Methods2 access a specific attribute averaged over all attributes in the class.A high value of cohesion (a low lack of cohesion) implies that the classis well designed. Lack Of Cohesion Of Measures the dissimilarity ofmethods in a class Methods 3 by attributes. A low value indicates goodclass subdivision, implying simplicity and high reusability. A high lackof cohesion increases complexity, thereby increasing the likelihood oferrors during the development process.

TABLE 3 Complexity Metrics Complexity Metrics Description AttributeDefined as the sum of each attribute's value in the class. ComplexityCyclomatic Represents the cognitive complexity of the class. It countsComplexity the number of possible paths through an algorithm by countingthe number of distinct regions on a flowgraph, i.e., the number of ‘if,’‘for’ and ‘while’ statements in the operation's body. Number Processesall of the methods and constructors, and counts Of the number ofdifferent remote methods called. A remote Remote method is defined as amethod which is not declared in Methods either the class itself or itsancestors. Response Calculated as ‘Number of Local Methods’ + ‘Number ofFor Remote Methods.’ A class which provides a larger response Class setis considered to be more complex and requires more testing than one witha smaller overall design complexity. Weighted The sum of the complexityof all methods for a class, where Methods each method is weighted by itscyclomatic complexity. The Per number of methods and the complexity ofthe methods Class 1 involved is a predictor of how much time and effortis required to develop and maintain the class. Weighted Measures thecomplexity of a class, assuming that a class Methods with more methodsthan another is more complex, and that Per a method with more parametersthan another is also likely Class 2 to be more complex.

TABLE 4 Coupling Metrics Coupling Metrics Description CouplingRepresents the number of other classes to which a class is Betweencoupled. Counts the number of reference types that are used Objects inattribute declarations, formal parameters, return types, throwsdeclarations and local variables, and types from which attribute andmethod selections are made. Excessive coupling between objects isdetrimental to modular design and prevents reuse. The more independent aclass is, the easier it is to reuse it in another application. In orderto improve modularity and promote encapsulation, inter-object classcouples should be kept to a minimum. The larger the number of couples,the higher the sensitivity to changes in other parts of the design, andtherefore maintenance is more difficult. A measure of coupling is usefulto determine how complex the testing of various parts of a design islikely to be. The higher the inter-object class coupling, the morerigorous the testing needs to be. Data Counts the number of referencetypes used in the attribute Abstraction declarations. Coupling FanOutCounts the number of reference types that are used in attributedeclarations, formal parameters, return types, throws declarations andlocal variables.

TABLE 5 Halstead Metrics Halstead Metrics Description Halstead Thismeasure is one of the Halstead Software Science Difficulty metrics. Itis calculated as (‘Number of Unique Operators’/ ‘Number of UniqueOperands’) * (‘Number of Operands’/ ‘Number of Unique Operands’).Halstead This measure is one of the Halstead Software Science Effortmetrics. It is calculated as ‘Halstead Difficulty’ * ‘Halstead ProgramVolume.’ Halstead This measure is one of the Halstead Software ScienceProgram metrics. It is calculated as ‘Number of Operators’ + Length‘Number of Operands.’ Halstead This measure is one of the HalsteadSoftware Science Program metrics. It is calculated as ‘Number of UniqueOperators’ + Vocabulary ‘Number of Unique Operands.’ Halstead Thismeasure is one of the Halstead Software Science Program metrics. It iscalculated as ‘Halstead Program Length’ * Volume Log2(‘Halstead ProgramVocabulary’). Number Of This measure is used as an input to the HalsteadSoftware Operands Science metrics. It counts the number of operands usedin a class. Number Of This measure is used as an input to the HalsteadSoftware Operators Science metrics. It counts the number of operatorsused in a class. Number Of This measure is used as an input to theHalstead Software Unique Science metrics. It counts the number of uniqueoperands Operands used in a class. Number Of This measure is used as aninput to the Halstead Software Unique Science metrics. It counts thenumber of unique operators Operators used in a class.

TABLE 6 Inheritance Metrics Inheritance Metrics Description Depth OfCounts how far down the inheritance hierarchy a class or Inheritanceinterface is declared. High values imply that a class is quite Hierarchyspecialized. Number Of Counts the number of classes which inherit from aChild particular class, i.e., the number of classes in the Classesinheritance tree down from a class. Non-zero value indicates that theparticular class is being re-used. The abstraction of the class may bepoor if there are too many child classes. It should also be stated thata high value of this measure points to the definite amount of testingrequired for each child class.

TABLE 7 Maximum Metrics Maximum Metrics Description Maximum Counts themaximum depth of ‘if,’ ‘for’ and ‘while’ Number Of branches in thebodies of methods. Logical units with a Levels large number of nestedlevels may need implementation simplification and process improvementbecause groups that contain more than seven pieces of information areincreasingly harder for people to understand in problem solving. MaximumDisplays the maximum number of parameters among all Number Of classoperations. Methods with many parameters tend to be Parameters morespecialized and, thus, are less likely to be reusable. Maximum Countsthe maximum size of the operations for a class. Size Of Method size isdetermined in terms of cyclomatic Operation complexity, i.e., the numberof ‘if,’ ‘for’ and ‘while’ statements in the operation's body.

TABLE 8 Polymorphism Metrics Polymorphism Metrics Description Number OfCounts the number of operations added by a class. A Added large value ofthis measure indicates that the functionality Methods of the given classbecomes increasingly distinct from that of the parent classes. In thiscase, it should be considered whether this class genuinely should beinheriting from the parent, or if it could be broken down into severalsmaller classes. Number Of Counts the number of inherited operationswhich a class Overridden overrides. Classes without parents are notprocessed. Methods High values tend to indicate design problems, i.e.,subclasses should generally add to and extend the functionality of theparent classes rather than overriding them.

TABLE 9 Ratio Metrics Ratio Metrics Description Comment Counts the ratioof comments to total lines of code Ratio including comments. PercentageCounts the percentage of package members in a class. Of Package MembersPercentage Counts the percentage of private members in a class. OfPrivate Members Percentage Counts the percentage of protected members ina class. Of Protected Members Percentage Counts the proportion ofvulnerable members in a class. A Of Public large proportion of suchmembers means that the class has Members high potential to be affectedby external classes and means that increased efforts will be needed totest such a class thoroughly. True Counts the ratio of comments to totallines of code Comment excluding comments. Ratio

The QA module also provides audits, i.e., the module checks forconformance to predefined or user-defined styles. The types of auditsprovided by the module include coding style, critical errors,declaration style, documentation, naming style, performance, possibleerrors and superfluous content. Examples of these audits with theirrespective definitions are identified in Tables 10–17 below.

TABLE 10 Coding Style Audits Coding Style Audits Description Access OfStatic members should be referenced through class names Static ratherthan through objects. Members Through Objects Assignment Formalparameters should not be assigned. To Formal Parameters Complex Checksfor the occurrence of multiple assignments and Assignment assignments tovariables within the same expression. Complex assignments should beavoided since they decrease program readability. Don't Use The negationoperator slows down the readability of the the Negation program. Thus,it is recommended that it not be used Operator frequently. FrequentlyOperator ‘?:’ The operator ‘?:’ makes the code harder to read than theMay Not Be alternative form with an if-statement. Used Provide Checks ifthe third argument of the ‘for’-statement is Incremental missing. InFor- Statement or use while- statement Replacement Demandimport-declarations must be replaced by a list of For Demand singleimport-declarations that are actually imported into Imports thecompilation unit. In other words, import-statements may not end with anasterisk. Use Use the abbreviated assignment operator in order to writeAbbreviated programs more rapidly. Also some compilers run fasterAssignment with the abbreviated assignment operator. Operator Use ‘this’Tries to make the developer use ‘this’ explicitly when Explicitly Totrying to access class members. Using the same class Access Class membernames with parameter names often makes what the Members developer isreferring to unclear.

TABLE 11 Critical Errors Audits Critical Errors Audits Description AvoidHiding Detects when attributes declared in child classes hide Inheritedinherited attributes. Attributes Avoid Hiding Detects when inheritedstatic operations are hidden by Inherited child classes. Static MethodsCommand Prevents methods that return a value from a modifying Querystate. The methods used to query the state of an object Separation mustbe different from the methods used to perform commands (change the stateof the object). Hiding Of Declarations of names should not hide otherdeclarations Names of the same name. Inaccessible Overload resolutiononly considers constructors and Constructor Or methods that are visibleat the point of the call. If, Method however, all the constructors andmethods were Matches considered, there may be more matches. This rule isviolated in this case. Imagine that ClassB is in a different packagethan ClassA. Then the allocation of ClassB violates this rule since thesecond constructor is not visible at the point of the allocation, but itstill matches the allocation (based on signature). Also the call to openin ClassB violates this rule since the second and the third declarationsof open are not visible at the point of the call, but it still matchesthe call (based on signature). Multiple Multiple declarations with thesame name must not be Visible simultaneously visible except foroverloaded methods. Declarations With Same Name Overriding a Checks forabstract methods overriding non-abstract Non-Abstract methods in asubclass. Method With an Abstract Method Overriding a A subclass shouldnot contain a method with the same Private Method name and signature asin a superclass if these methods are declared to be private. OverloadingA superclass method may not be overloaded within a Within a subclassunless all overloading in the superclass are also Subclass overridden inthe subclass. It is very unusual for a subclass to be overloadingmethods in its superclass without also overriding the methods it isoverloading. More frequently this happens due to inconsistent changesbetween the superclass and subclass - i.e., the intention of the user isto override the method in the superclass, but due to the error, thesubclass method ends up overloading the superclass method. Use of StaticNon-final static attributes should not be used in Attribute forinitializations of attributes. Initialization

TABLE 12 Declaration Style Audits Declaration Style Audits DescriptionBadly Array declarators must be placed next to the type descriptorLocated of their component type. Array Declarators Constant Privateattributes that never get their values changed must Private be declaredfinal. By explicitly declaring them in such a Attributes way, a readerof the source code get some information of Must Be how the attribute issupposed to be used. Final Constant Local variables that never get theirvalues changed must be Variables declared final. By explicitly declaringthem in such a way, a Must Be reader of the source code obtainsinformation about how the Final variable is supposed to be used. DeclareSeveral variables (attributes and local variables) should not VariablesIn be declared in the same statement. One Statement Each InstantiatedThis rule recommends making all instantiated classes final. Classes Itchecks classes which are present in the object model. Should Be Classesfrom search/classpath are ignored. Final List All Enforces a standard toimprove readability. Methods/data in Public And your class should beordered properly. Package Members First Order Of Checks for correctordering of modifiers. For classes, this Appearance includes visibility(public, protected or private), abstract, Of Modifiers static, final.For attributes, this includes visibility (public, protected or private),static, final, transient, volatile. For operations, this includesvisibility (public, protected or private), abstract, static, final,synchronized, native. Put the Main Tries to make the program comply withvarious coding Function standards regarding the form of the classdefinitions. Last

TABLE 13 Documentation Audits Documentation Audits Description Bad TagIn This rule verifies code against accidental use of improper JavaDocJavaDoc tags. Comments Distinguish Checks whether the JavaDoc commentsin your program Between ends with ‘**/’ and ordinary C-style ones with‘*/.’ JavaDoc And Ordinary Comments

TABLE 14 Naming Style Audits Naming Style Audits Description Class NameChecks whether top level classes or interfaces have the Must Match samename as the file in which they reside. Its File Name Group Enforcesstandard to improve readability. Operations With Same Name TogetherNaming Takes a regular expression and item name and reports allConventions occurrences where the pattern does not match thedeclaration. Names Of Names of classes which inherit from Exceptionshould Exception end with Exception. Classes Use One-character localvariable or parameter names should Conventional be avoided, except fortemporary and looping variables, Variable or where a variable holds anundistinguished value of a Names type.

TABLE 15 Performance Audits Performance Audits Description Avoid Thisrule recommends declaring local variables outside the Declaring loopssince declaring variables inside the loop is less Variables efficient.Inside Loops Append To Performance enhancements can be obtained byreplacing String String operations with StringBuffer operations if aString Within a object is appended within a loop. Loop Complex Avoidusing complex expressions as repeat conditions Loop within loops.Expressions

TABLE 16 Possible Error Audits Possible Error Audits Description AvoidPublic Declare the attributes either private or protected, and AndPackage provide operations to access or change them. Attributes AvoidAvoid statements with empty body. Statements With Empty Body Assignment‘For’-loop variables should not be assigned. To For-Loop Variables Don'tCompare Avoid testing for equality of floating point numbers sinceFloating floating-point numbers that should be equal are not Point Typesalways equal due to rounding problems. Enclosing The statement of a loopmust always be a block. The Body Within ‘then’ and ‘else’ parts of‘if’-statements must always be a Block blocks. This makes it easier toadd statements without accidentally introducing bugs in case thedeveloper forgets to add braces. Explicitly Explicitly initialize allvariables. The only reason not to Initialize All initialize a variableis where it's declared is if the initial Variables value depends on somecomputation occurring first. Method Calling of super.finalize() fromfinalize() is good practice finalize() of programming, even if the baseclass doesn't define the Doesn't Call finalize() method. This makesclass implementations less super.finalize() dependent on each other.Mixing Logical An expression containing multiple logical operatorsOperators should be parenthesized properly. Without Parentheses No Useof assignment within conditions makes the source Assignments In codehard to understand. Conditional Expressions Use ‘equals’ The ‘==’operator used on strings checks if two string Instead Of ‘==’ objectsare two identical objects. In most situations, however, one likes tosimply check if two strings have the same value. In these cases, the‘equals’ method should be used. Use ‘L’ Instead It is better to useuppercase ‘L’ to distinguish the letter Of ‘l’ at the end ‘l’ from thenumber ‘1.’ of integer constant Use Of the The ‘synchronized’ modifieron methods can sometimes ‘synchronized’ cause confusion duringmaintenance as well as during Modifier debugging. This rule thereforerecommends against using this modifier, and instead recommends using‘synchronized’ statements as replacements.

TABLE 17 Superfluous Content Audits Superfluous Content AuditsDescription Duplicate There should be at most one import declarationthat Import imports a particular class/package. Declarations Don'tImport No classes or interfaces need to be imported from the the Packagethe package to which the source code file belongs. Source FileEverything in that package is available without explicit Belongs Toimport statements. Explicit Import Explicit import of classes from thepackage ‘java.lang’ Of the should not be performed. java.lang ClassesEquality Avoid performing equality operations on Boolean Operations Onoperands. ‘True’ and ‘false’ literals should not be used Boolean inconditional clauses. Arguments Imported Items It is not legal to importa class or an interface and never Must Be Used use it. This rule checksclasses and interfaces that are explicitly imported with their names -that is not with import of a complete package, using an asterisk. Ifunused class and interface imports are omitted, the amount ofmeaningless source code is reduced - thus the amount of code to beunderstood by a reader is minimized. Unnecessary Checks for the use oftype casts that are not necessary. Casts Unnecessary Verifies that theruntime type of the left-hand side ‘instanceof’ expression is the sameas the one specified on the Evaluations right-hand side. Unused LocalLocal variables and formal parameter declarations must Variables And beused. Formal Parameters Use Of The modifier ‘abstract’ is consideredobsolete and should Obsolete not be used. Interface Modifier Use Of Allinterface operations are implicitly public and abstract. Unnecessary Allinterface attributes are implicitly public, final and Interface static.Member Modifiers Unused Private An unused class member might indicate alogical flaw in Class Member the program. The class declaration has tobe reconsidered in order to determine the need of the unused member(s).

If the QA module determines that the source code does not conform, anerror message is provided to the developer. For example, as depicted inFIG. 8A, the software development tool checks for a variety of codingstyles 800. If the software development tool were to check for “AccessOf Static Members Through Objects” 802, it would verify whether staticmembers are referenced through class names rather than through objects804. Further, as depicted in FIG. 8B, if the software development toolwere to check for “Complex Assignment” 806, the software developmenttool would check for the occurrence of multiple assignments andassignments to variables within the same expression to avoid complexassignments since these decrease program readability 808. An example ofsource code having a complex assignment 810 and source code having anon-complex assignment 812 are depicted in FIGS. 8B and 8C,respectively. The QA module of the software development tool monitorsthe source code for other syntax errors well known in the art, asdescribed above, and provides an error message if any such errors aredetected.

The improved software development tool of the present invention is usedto develop source code in a project. The project comprises a pluralityof files and the source code of one of the plurality of files is writtenin a given language. The software development tool determines thelanguage of the source code of the file, converts the source code fromthe language into a language-neutral representation, uses thelanguage-neutral representation to textually display the source code ofthe file in the language, and uses the language-neutral representationto display a graphical representation of at least a portion of theproject. The source code and the graphical representation are displayedsimultaneously.

The improved software development tool of the present invention is alsoused to develop source code. The software development tool receives anindication of a selected language for the source code, creates a file tostore the source code in the selected language, converts the source codefrom the selected language into a language-neutral representation, usesthe language-neutral representation to display the source code of thefile, and uses the language-neutral representation to display agraphical representation of the file. Again, the source code and thegraphical representation are displayed simultaneously.

Moreover, if the source code in the file is modified, the modifiedsource code and a graphical representation of at least a portion of themodified source code are displayed simultaneously. The QA module of thesoftware development tool provides an error message if the modificationdoes not conform to predefined or user-defined styles, as describedabove. The modification to the source code may be received from thedisplay of the source code, the display of the graphical representationof the project, or via some other independent software to modify thecode. The graphical representation of the project may be in UnifiedModeling Language; however, one skilled in the art will recognize thatother graphical representations of the source code may be displayed.Further, although the present invention is described and shown using thevarious views of the UML, one of ordinary skill in the art willrecognize that other views may be displayed.

FIG. 9 depicts a flow diagram of the steps performed by the softwaredevelopment tool to develop a project in accordance with the presentinvention. As previously stated, the project comprises a plurality offiles. The developer either uses the software development tool to open afile which contains existing source code, or to create a file in whichthe source code will be developed. If the software development tool isused to open the file, determined in step 900, the software developmenttool initially determines the programming language in which the code iswritten (step 902). The language is identified by the extension of thefile, e.g., “java” identifies source code written in the Java™ language,while “.cpp” identifies source code written in C++. The softwaredevelopment tool then obtains a template for the current programminglanguage, i.e., a collection of generalized definitions for theparticular language that can be used to build the data structure (step904). For example, the definition of a new Java™ class contains adefault name, e.g., “Class1,” and the default code, “public class Class1{ }.” Such templates are well known in the art. For example, the“Microsoft Foundation Class Library” and the “Microsoft Word TemplateFor Business Use Case Modeling” are examples of standard templatelibraries from which programmers can choose individual template classes.The software development tool uses the template to parse the source code(step 906), and create the data structure (step 908). After creating thedata structure or if there is no existing code, the software developmenttool awaits an event, i.e., a modification or addition to the sourcecode by the developer (step 910). If an event is received and the eventis to close the file (step 912), the file is saved (step 914) and closed(step 916). Otherwise, the software development tool performs the event(step 918), i.e., the tool makes the modification. The softwaredevelopment tool then updates the TMM or model (step 920), as discussedin detail below, and updates both the graphical and the textual views(step 922).

FIGS. 10A and 10B depict a flow diagram illustrating the update modelstep of FIG. 9. The software development tool selects a file from theproject (step 1000), and determines whether the file is new (step 1002),whether the file has been updated (step 1004), or whether the file hasbeen deleted (step 1006). If the file is new, the software developmenttool adds the additional symbols from the file to the TMM (step 1008).To add the symbol to the TMM, the software development tool uses thetemplate to parse the symbol to the TMM. If the file has been updated,the software development tool updates the symbols in the TMM (step1010). Similar to the addition of a symbol to the TMM, the softwaredevelopment tool uses the template to parse the symbol to the TMM. Ifthe file has been deleted, the software development tool deletes thesymbols in the TMM (step 1012). The software development tool continuesthis analysis for all files in the project. After all files are analyzed(step 1014), any obsolete symbols in the TMM (step 1016) are deleted(step 1018).

FIG. 11 depicts a flow diagram illustrating the performance of an event,specifically the creation of a class, in accordance with the presentinvention. After identifying the programming language (step 1100), thesoftware development tool obtains a template for the language (step1102), creates a source code file in the project directory (step 1104),and pastes the template onto the TMM (step 1106). The project directorycorresponds to the SCI model 302 of FIG. 3. Additional events which adeveloper may perform using the software development tool include thecreation, modification or deletion of packages, projects, attributes,interfaces, links, operations, and the closing of a file.

The software development tool is collectively broken into three views ofthe application: the static view, the dynamic view, and the functionalview. The static view is modeled using the use-case and class diagrams.A use case diagram 1200, depicted in FIG. 12, shows the relationshipamong actors 1202 and use cases 1204 within the system 1206. A classdiagram 1300, depicted in FIG. 13 with its associated source code 1302,on the other hand, includes classes 1304, interfaces, packages and theirrelationships connected as a graph to each other and to their contents.

The dynamic view is modeled using the sequence, collaboration andstatechart diagrams. As depicted in FIG. 14, a sequence diagram 1400represents an interaction, which is a set of messages 1402 exchangedamong objects 1404 within a collaboration to effect a desired operationor result. In a sequence diagram 1400, the vertical dimension representstime and the horizontal dimension represents different objects. Acollaboration diagram 1500, depicted in FIG. 15, is also an interactionwith messages 1502 exchanged among objects 1504, but it is also acollaboration, which is a set of objects 1504 related in a particularcontext. Contrary to sequence diagrams 1400 (FIG. 14), which emphasizethe time ordering of messages along the vertical axis, collaborationdiagrams 1500 (FIG. 15) emphasize the structural organization ofobjects.

A statechart diagram 1600 is depicted in FIG. 16. The statechart diagram1600 includes the sequences of states 1602 that an object or interactiongoes through during its life in response to stimuli, together with itsresponses and actions. It uses a graphic notation that shows states ofan object, the events that cause a transition from one state to another,and the actions that result from the transition.

The functional view can be represented by activity diagrams 1700 andmore traditional descriptive narratives such as pseudocode andminispecifications. An activity diagram 1700 is depicted in FIG. 17, andis a special case of a state diagram where most, if not all, of thestates are action states 1702 and where most, if not all, of thetransitions are triggered by completion of the actions in the sourcestates. Activity diagrams 1700 are used in situations where all or mostof the events represent the completion of internally generated actions.

There is also a fourth view mingled with the static view called thearchitectural view. This view is modeled using package, component anddeployment diagrams. Package diagrams show packages of classes and thedependencies among them. Component diagrams 1800, depicted in FIG. 18,are graphical representations of a system or its component parts.Component diagrams 1800 show the dependencies among software components,including source code components, binary code components and executablecomponents. As depicted in FIG. 19, Deployment diagrams 1900 are used toshow the distribution strategy for a distributed object system.Deployment diagrams 1900 show the configuration of run-time processingelements and the software components, processes and objects that live onthem.

Although discussed in terms of class diagrams, one skilled in the artwill recognize that the software development tool of the presentinvention may support these and other graphical views.

The improved software development tool of the present invention is usedto display versions of source code. Each version is an instance in anedit history. The software development tool determines a language of thesource code, stores indications of the edits to the source code,converts the source code with the indications of the edits from thelanguage into a language-neutral representation, uses thelanguage-neutral representation to display the source code in thelanguage with the indications of the edits, and uses thelanguage-neutral representation to display the corresponding graphicalrepresentation of the source code with the indications of the edits. Therate at which the source code with the indications of the edits isdisplayed is adjustable. Moreover, the source code with the indicationsof the edits may be displayed sequentially or in reverse order.

FIG. 20 depicts a flow diagram of the steps performed by the softwaredevelopment tool to store the edit history of source code. After thesource code has been modified (step 2000), the software development toolsaves the edits to the source code into the secondary storage (step2002). After all edits have been made (step 2004), the softwaredevelopment tool saves the source code into the secondary storage (step2006).

The steps performed by the software development tool to sequentiallydisplay the source code with the edit history is depicted in FIGS.21A–C. The software development tool retrieves the source code (step2100), identifies the programming language of the source code (step2102), and obtains the template for the current programming language(step 2104). The software development tool then parses the source code(step 2106) and creates the data structure (step 2108). The softwaredevelopment tool retrieves the edit history, i.e., all of the editswhich were stored for the source code (step 2110), and the user choosesa rate of displaying the source code (step 2112), thus setting the timeperiod (step 2114). The user chooses whether to display the source codein the forward mode or in the reverse mode (step 2116).

In the forward mode shown in FIG. 21B, the software development toolremoves all edits to the source code (step 2118) and updates the model(step 2120). The software development tool pauses for the time perioddetermined by the rate at which the source code is displayed (step2122), and for each edit (step 2124), the software development toolapplies the edit to the source code (step 2126) before updating themodel (step 2128). If the user chooses to adjust the rate of the display(step 2130), the time period is adjusted accordingly (step 2132). Theprocess then continues with the next edit (step 2134).

In the reverse mode depicted in FIG. 21C, the software development toolpauses for the time period (step 2136), and for each edit (step 2138),the software development tool removes the edit from the source code(step 2140) before updating the model (step 2142). If the user choosesto adjust the rate of the display (step 2144), the software developmenttool adjusts the time period accordingly (step 2146). The process thencontinues with the next edit (step 2148).

While various embodiments of the application have been described, itwill be apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible that are within the scopeof this invention. Accordingly, the invention is not to be restrictedexcept in light of the attached claims and their equivalents.

1. A method in a data processing system for displaying versions of asource code, each version reflecting an instance in an edit history, themethod comprising the steps of: determining the language of the sourcecode; storing indications of the edits to the source code; convertingthe source code with the indications of the edits from the language intoa language-neutral representation that includes a data structure havinga source code interface (SCI) model, an SCI package, an SCI class, andan SCI member; and using language-neutral representation tosimultaneously display a text representation and a correspondinggraphical representation of the converted source code with theindications of the edits, showing visual differences of the source codethrough time, wherein the graphical representation of the convertedsource code displays a diagrammatic representation of the source code todemonstrate relationships between elements of the source code, andwherein the graphical representation of the source code is not analpha-numeric display and is not merely a text representation on a userinterface, and calculating metrics selected from a group consisting ofbasic metrics, cohesion metrics, complexity metrics, coupling metrics,Halstead metrics, inheritance metrics, maximum metrics, polymorphismmetrics, and maximum metrics by way of a quality assurance module, whichmonitors the modifications to the source code.
 2. The method of claim 1,wherein the source code and the corresponding graphical representationof the converted source code are displayed sequentially.
 3. The methodof claim 1, wherein a rate at which the source code with the indicationsof the edits is displayed is adjustable.
 4. The method of claim 1,wherein the source code with the indications of the edits is displayedin reverse order.
 5. The method of claim 1, wherein the graphicalrepresentation is one from a group consisting of a use case diagram, asequence diagram, a collaboration diagram, a state transition diagram,an activity diagram, a package diagram, a component diagram and adeployment diagram.
 6. A method in a data processing system fordisplaying versions of a source code, the method comprising the stepsof: storing an edit to the source code; and displaying simultaneously atext representation and a corresponding language-neutral graphicalrepresentation of the source code that includes a data structure havinga source code interface (SCI) model, an SCI package, an SCI class, andan SCI member with an indication of the edit, wherein thelanguage-neutral graphical representation of the source code displays adiagrammatic representation of the source code demonstratingrelationships between elements of the source code, and wherein thelanguage-neutral graphical representation of the source code is not analpha-numeric numeric display and is not merely a text representation ona user interface, and calculating metrics selected from a groupconsisting of basic metrics, cohesion metrics, complexity metrics,coupling metrics, Halstead metrics, inheritance metrics, maximummetrics, polymorphism metrics, and maximum metrics by way of a qualityassurance module, which monitors the modifications to the source code.7. The method of claim 5, wherein the step of displaying the source codecomprises the steps of: determining a language of the source code;converting the source code from the language into the language-neutralgraphical representation that includes a data structure having a sourcecode interface (SCI) model, an SCI package, an SCI class, and an SCImember; and using the language-neutral graphical representation tosimultaneously display a text representation and a graphicalrepresentation of the converted source code with an indication of thesource code edit.
 8. The method of claim 7, wherein the source code isdisplayed after the converted source code with an indication of the editis displayed.
 9. A computer-readable medium containing instructions forcontrolling a data processing system to perform a method, the dataprocessing system having versions of a source code, each versionreflecting an instance in an edit history, the method comprising thesteps of: determining a language of the source code; storing indicationsof the edits to the source code; converting the source code with theindications of the edits from the language into a language-neutralrepresentation that includes a data structure having a source codeinterface (SCI) model, an SCI package, an SCI class, and an SCI member;and using the language-neutral representation to simultaneously displaya text representation and a corresponding graphical representation ofthe source code with indications of all the edits; wherein the graphicalrepresentation of the source code displays a diagrammatic representationof the source code demonstrating relationships between elements of thesource code, and wherein the graphical representation of the source codeis not an alpha-numeric display and is not merely a text representationon a user interface, and calculating metrics selected from a groupconsisting of basic metrics, cohesion metrics, complexity metrics,coupling metrics, Halstead metrics, inheritance metrics, maximummetrics, polymorphism metrics, and maximum metrics by way of a qualityassurance module, which monitors the modifications to the source code.10. The computer-readable medium of claim 9, wherein the source code andthe corresponding graphical representation of the source code aredisplayed sequentially.
 11. The computer-readable medium of claim 9,wherein a rate at which the source code with the indications of theedits is displayed is adjustable.
 12. The computer-readable medium ofclaim 9, wherein the source code with the indications of the edits isdisplayed in reverse order.
 13. The computer-readable medium of claim 9,wherein the graphical representation is one from a group consisting of aclass diagram, a use case diagram, a sequence diagram, a collaborationdiagram, a state transition diagram, an activity diagram, a packagediagram, a component diagram and a deployment diagram.
 14. Acomputer-readable medium containing instructions for controlling a dataprocessing system to perform a method, the data processing system havingversions of a source code, each version reflecting an instance in anedit history, the method comprising the steps of: storing indications ofthe edits to the source code; and displaying simultaneously a textrepresentation and a language-neutral graphical representation of thesource code that includes a data structure having a source codeinterface (SCI) model, an SCI package, an SCI class, and an SCI memberwith indications of all the edits, wherein the language-neutralgraphical representation of the source code of the source code displaysa diagrammatic representation of the source code to demonstraterelationships between elements of the source code, and wherein thelanguage-neutral graphical representation of the source code is not analpha-numeric display and is not merely a text representation on a userinterface, and calculating metrics selected from a group consisting ofbasic metrics, cohesion metrics, complexity metrics, coupling metrics,Halstead metrics, inheritance metrics, maximum metrics, polymorphismmetrics, and maximum metrics by way of a quality assurance module, whichmonitors the modifications to the source code.
 15. The computer-readablemedium of claim 14, wherein the versions of the source code aredisplayed sequentially.
 16. The computer-readable medium of claim 14,wherein a rate at which the source code with the indications of theedits is displayed is adjustable.
 17. The computer-readable medium ofclaim 14, wherein the source code with the indications of the edits isdisplayed in reverse order.
 18. The computer-readable medium of claim14, wherein the language-neutral graphical representation is one from agroup consisting of a class diagram, a use diagram, a sequence diagram,a collaboration diagram, a state transition diagram, an activitydiagram, a package diagram, a component diagram and a deploymentdiagram.
 19. A computer-readable medium containing instructions forcontrolling a data processing system to perform a method, the dataprocessing system having a source code, the method comprising the stepsof: storing an edit to the source code; displaying simultaneously a textrepresentation and a language-neutral graphical representation of thesource code that includes a data structure having a source codeinterface (SCI) model, an SCI package, an SCI class, and an SCI memberwith indications of all the edits, wherein the language-neutralgraphical representation of the source code displays a diagrammaticrepresentation of the source code to demonstrate relationships betweenelements of the source code, and wherein the language-neutral graphicalrepresentation of the source code is not an alpha-numeric display and isnot merely a text representation on a user interface, and calculatingmetrics selected from a group consisting of cohesion metrics, complexitymetrics, coupling metrics, Halstead metrics, inheritance metrics,maximum metrics, polymorphism metrics, and maximum metrics by way of aquality assurance module, which monitors the modifications to the sourcecode.
 20. The computer-readable medium of claim 19, wherein the step ofdisplaying the source code comprises the steps of: determining alanguage of the source code; converting the source code from thelanguage into the language-neutral representation; and using thelanguage-neutral representation to simultaneously display a textrepresentation and a corresponding graphical representation of theconverted source code with an indication of the edit.
 21. Thecomputer-readable medium of claim 19, wherein the step of displaying thesource code with the edit comprises the steps of: converting the sourcecode with an indication of the edit from the language into thelanguage-neutral graphical representation; and using thelanguage-neutral representation of the converted source code with anindication of the edit to display the graphical representation of thesource code with the edit.
 22. The computer-readable medium of claim 19,wherein the source code is displayed after the source code with the editis displayed.
 23. A data processing system comprising: a secondarystorage including a source code; a memory device including: a programthat stores indications of edits to the source code into the memorydevice, and that simultaneously displays a text representation and acorresponding language-neutral graphical representation of the sourcecode that includes a data structure having a source code interface (SCI)model, an SCI package, an SCI class, and an SCI member with indicationsof all edits, wherein the language-neutral graphical representation ofthe source code displays a diagrammatic representation of the sourcecode to demonstrate relationships between elements of the source code,and wherein the language-neutral graphical representation of the sourcecode is not an alpha-numeric display and is not merely a textrepresentation on a user interface of the source code with theindications of the edits; a quality assurance module which monitors themodifications to the source code and calculates metrics selected from agroup consisting of basic metrics, cohesion metrics, complexity metrics,coupling metrics, Halstead metrics, inheritance metrics, maximum metricspolymorphism metrics, and maximum metrics; and a processor for runningthe program.
 24. The data processing system of claim 23, wherein thesource code with the indications of the edits are displayedsequentially.
 25. The data processing system of claim 23, wherein a rateat which the source codes with the indications of the edits is displayedis adjustable.
 26. The data processing system of claim 23, wherein thesource code with the indications of the edits is displayed in reverseorder.
 27. The data processing system of claim 23, wherein the programfurther determines the language of the source code, converts the sourcecode with the indications of the edits from the language into thelanguage-neutral graphical representation, and uses the language-neutralgraphical representation to simultaneously display a text representationand a corresponding graphical representation of the source code withindications of all the edits.
 28. The data processing system of claim27, wherein the memory device further comprises a transient meta model,wherein said transient meta model stores the language neutral graphicalrepresentation of the source code.
 29. The data processing system ofclaim 23, wherein the graphical representation is one from a groupconsisting of a class diagram, a use case diagram, a sequence diagram, acollaboration diagram, a state transition diagram, an activity diagram,a package diagram, a component diagram and a deployment diagram.
 30. Asystem for displaying versions of a source code, each version reflectingan instance in an edit history, the system comprising: means for storingindications of the edits to the source code; and means forsimultaneously displaying a text representation and a language-neutralgraphical representation of the source code that includes a datastructure having a source code interface (SCI) model, an SCI package, anSCI class, and an SCI member with the indications of all the edits,wherein the graphical representation of the source code displays adiagrammatic representation of the source code to demonstraterelationships between elements of the source code, and wherein thegraphical representation of the source code is not an alpha-numericdisplay and is not merely a text representation on a user interface, anda means for calculating metrics selected from a group consisting ofbasic metrics, cohesion metrics, complexity metrics, coupling metrics,Halstead metrics, inheritance metrics, maximum metrics, polymorphismmetrics, and maximum metrics.